As a parking position guidance system capable of guiding to a parking position that conforms to user's preference with high accuracy, and of guiding to a parking position even in a parking lot that user has not used, PTL 1 describes a parking lot side device that is provided with a parking lot information DB storing parking tastes when a large number of vehicles have parked in a parking lot and determines a parking instruction position based on the parking lot information DB and taste information of a vehicle user transmitted from an in-vehicle parking position guide device.